--- /dev/null
+(**************************************************************************)
+(* ___ *)
+(* ||M|| *)
+(* ||A|| A project by Andrea Asperti *)
+(* ||T|| *)
+(* ||I|| Developers: *)
+(* ||T|| The HELM team. *)
+(* ||A|| http://helm.cs.unibo.it *)
+(* \ / *)
+(* \ / This file is distributed under the terms of the *)
+(* v GNU General Public License Version 2 *)
+(* *)
+(**************************************************************************)
+
+include "static_2/syntax/tdeq.ma".
+include "static_2/syntax/toeq.ma".
+
+(* SORT-IRRELEVANT OUTER EQUIVALENCE FOR TERMS ******************************)
+
+(* Properties with sort-irrelevant equivalence for terms ********************)
+
+lemma tdeq_toeq: ∀T1,T2. T1 ≛ T2 → T1 ⩳ T2.
+#T1 #T2 * -T1 -T2 /2 width=1 by toeq_sort, toeq_pair/
+qed.